Fossilised dermal tissue associated with Australopithecus sediba

Abstract

The near-complete Plio-Pleistocene-aged Australopithecus sediba hominin specimens from the Malapa site, South Africa were analysed to determine whether soft tissue in the form of fossilised skin might have been preserved. The taphonomic condition of the fossils suggests rapid burial, lack of predation, but with some insect damage, making the preservation environment at Malapa exceptional. Any potential soft tissue found with the hominins, represented by Malapa Hominid 1 (MH1) and Malapa Hominid 2 (MH2), was valuable to examine because such preservation is unrecognised in the early hominin record. Two primary specimens were analysed – a sample associated closely with the cranium of MH1 and a specimen associated with the mandible of MH2. A multidisciplinary approach that combined morphological techniques (optical coherence tomography, three-dimensional laser scans, micro-CT scans and light microscopy) in association with molecular imaging (Raman spectroscopy and Fourier Transform Infrared) was used to investigate whether original organics might be recovered. A null hypothesis was formulated and based on the findings from the six non-destructive techniques it was rejected. Soft tissue had seemingly been preserved, in a fossilised form, with the Malapa hominin samples based on the findings from the six non-destructive techniques.